diff --git a/crlcore/src/ccore/Catalog.cpp b/crlcore/src/ccore/Catalog.cpp
index 26bb3723..8f691bd8 100644
--- a/crlcore/src/ccore/Catalog.cpp
+++ b/crlcore/src/ccore/Catalog.cpp
@@ -27,7 +27,7 @@ using namespace std;
 namespace CRL {
 
 
-  const char* MissingStateProperty   = "%s:\n\n  Missing Catalog State Property in cell \"%s\".\n";
+  const char* MissingStateProperty = "%s:\n\n  Missing Catalog State Property in cell \"%s\".\n";
 
 
 // -------------------------------------------------------------------
@@ -41,6 +41,17 @@ namespace CRL {
   }
 
 
+  Cell* Catalog::State::setCell ( Cell* cell )
+  {
+    _cell = cell;
+    if (_cell) {
+      if (isPad ()) _cell->setPad ( true );
+      if (isFeed()) _cell->setFeed( true );
+    }
+    return _cell;
+  }
+
+
   void   Catalog::State::merge ( const State& other )
   {
     if ( (_cell   ==NULL) && other._cell    ) _cell    = other._cell;
@@ -78,7 +89,6 @@ namespace CRL {
     return record;
   }
 
-
 // -------------------------------------------------------------------
 // Class  :  "Catalog".
 
diff --git a/crlcore/src/ccore/crlcore/Catalog.h b/crlcore/src/ccore/crlcore/Catalog.h
index 73a9f4ed..0b272450 100644
--- a/crlcore/src/ccore/crlcore/Catalog.h
+++ b/crlcore/src/ccore/crlcore/Catalog.h
@@ -112,7 +112,7 @@ namespace CRL {
           inline unsigned int  getDepth       () const;
         // Modifiers.
           inline void          merge          ( const State& other );
-          inline Cell*         setCell        ( Cell* cell );
+                 Cell*         setCell        ( Cell* cell );
           inline Library*      setLibrary     ( Library* library );
           inline void          setDepth       ( unsigned int depth );
         // Hurricane Management.
@@ -193,7 +193,6 @@ namespace CRL {
   inline bool              Catalog::State::setDelete        ( bool value ) { return setFlags(Delete     ,value); }
   inline bool              Catalog::State::setPhysical      ( bool value ) { return setFlags(Physical   ,value); }
   inline bool              Catalog::State::setLogical       ( bool value ) { return setFlags(Logical    ,value); }
-  inline Cell*             Catalog::State::setCell          ( Cell* cell ) { return _cell = cell; }
   inline Library*          Catalog::State::setLibrary       ( Library* library ) { return _library = library; }
   inline void              Catalog::State::setDepth         ( unsigned int depth ) { _depth = depth; }
   inline Cell*             Catalog::State::getCell          () const { return _cell; }
diff --git a/hurricane/src/hurricane/Path.cpp b/hurricane/src/hurricane/Path.cpp
index 72c0253d..36a17c38 100644
--- a/hurricane/src/hurricane/Path.cpp
+++ b/hurricane/src/hurricane/Path.cpp
@@ -245,6 +245,19 @@ void Path::setNameSeparator(char nameSeparator)
     SharedPath::setNameSeparator(nameSeparator);
 }
 
+string Path::getCompactString() const
+// **********************************
+{
+  if (isEmpty()) return "<empty>";
+
+  string s = "<";
+  s += getString(getOwnerCell()->getName());
+  s += ":";
+  s += getString(_sharedPath->getName()) + ":";
+  s += getString(getMasterCell()->getName()) + ">";
+  return s;
+}
+
 string Path::_getString() const
 // ****************************
 {
diff --git a/hurricane/src/hurricane/hurricane/Cell.h b/hurricane/src/hurricane/hurricane/Cell.h
index 9ef539dd..0ea136a4 100644
--- a/hurricane/src/hurricane/hurricane/Cell.h
+++ b/hurricane/src/hurricane/hurricane/Cell.h
@@ -88,11 +88,12 @@ class Cell : public Entity {
                   , Terminal                = 0x00001000
                   , FlattenLeaf             = 0x00002000
                   , Pad                     = 0x00004000
-                  , FlattenedNets           = 0x00008000
-                  , Placed                  = 0x00010000
-                  , Routed                  = 0x00020000
-                  , MergedQuadTree          = 0x00040000
-                  , Materialized            = 0x00080000 
+                  , Feed                    = 0x00008000
+                  , FlattenedNets           = 0x00010000
+                  , Placed                  = 0x00020000
+                  , Routed                  = 0x00040000
+                  , MergedQuadTree          = 0x00080000
+                  , Materialized            = 0x00100000 
                   };
 
       public:
@@ -391,6 +392,7 @@ class Cell : public Entity {
     public: bool isUniquified() const;
     public: bool isUniquifyMaster() const;
     public: bool isPad() const {return _flags.isset(Flags::Pad);};
+    public: bool isFeed() const {return _flags.isset(Flags::Feed);};
     public: bool isFlattenedNets() const {return _flags.isset(Flags::FlattenedNets);};
     public: bool isPlaced() const {return _flags.isset(Flags::Placed);};
     public: bool isRouted() const {return _flags.isset(Flags::Routed);};
@@ -406,6 +408,7 @@ class Cell : public Entity {
     public: void setTerminal(bool isTerminal) {_flags.set(Flags::Terminal,isTerminal);};
     public: void setFlattenLeaf(bool isFlattenLeaf) {_flags.set(Flags::FlattenLeaf,isFlattenLeaf);};
     public: void setPad(bool isPad) {_flags.set(Flags::Pad,isPad);};
+    public: void setFeed(bool isFeed) {_flags.set(Flags::Feed,isFeed);};
     public: void flattenNets(unsigned int flags=Flags::BuildRings);
     public: void createRoutingPadRings(unsigned int flags=Flags::BuildRings);
     public: void setFlags(unsigned int flags) { _flags |= flags; }
diff --git a/hurricane/src/hurricane/hurricane/Path.h b/hurricane/src/hurricane/hurricane/Path.h
index 80dca474..bd5d4fc6 100644
--- a/hurricane/src/hurricane/hurricane/Path.h
+++ b/hurricane/src/hurricane/hurricane/Path.h
@@ -97,6 +97,7 @@ class Path {
 // Others
 // ******
 
+    public: string getCompactString() const;
     public: string _getTypeName() const { return _TName("Occurrence"); };
     public: string _getString() const;
     public: Record* _getRecord() const;
diff --git a/hurricane/src/viewer/CMakeLists.txt b/hurricane/src/viewer/CMakeLists.txt
index 25aed97f..344b80eb 100644
--- a/hurricane/src/viewer/CMakeLists.txt
+++ b/hurricane/src/viewer/CMakeLists.txt
@@ -36,6 +36,8 @@
                                     hurricane/viewer/SelectionWidget.h
                                     hurricane/viewer/NetlistModel.h
                                     hurricane/viewer/NetlistWidget.h
+                                    hurricane/viewer/HierarchyModel.h
+                                    hurricane/viewer/HierarchyWidget.h
                                     hurricane/viewer/DisplayFilterWidget.h
                                     hurricane/viewer/ControllerWidget.h
                                     hurricane/viewer/ScriptWidget.h
@@ -104,6 +106,9 @@
                                     NetInformations.cpp
                                     NetlistModel.cpp
                                     NetlistWidget.cpp
+                                    HierarchyInformations.cpp
+                                    HierarchyModel.cpp
+                                    HierarchyWidget.cpp
                                     DisplayFilterWidget.cpp
                                     ControllerWidget.cpp
                                     ScriptWidget.cpp
diff --git a/hurricane/src/viewer/CellViewer.cpp b/hurricane/src/viewer/CellViewer.cpp
index 226af418..f7dff57d 100644
--- a/hurricane/src/viewer/CellViewer.cpp
+++ b/hurricane/src/viewer/CellViewer.cpp
@@ -550,7 +550,10 @@ namespace Hurricane {
     list< shared_ptr<CellWidget::State> >::iterator istate = _cellHistory.begin();
     for ( size_t i=0 ; i<CellHistorySize ; i++ ) {
       if ( istate != _cellHistory.end() ) {
-        QString entry = tr("&%1: %2").arg(i+1).arg( getString((*istate)->getName()).c_str() );
+        QString entry = tr("&%1: %2 %3")
+          .arg(i+1)
+          .arg( getString((*istate)->getName()).c_str() )
+          .arg( (*istate)->getTopPath().getCompactString().c_str() );
         _cellHistoryAction[i]->setText    ( entry );
         _cellHistoryAction[i]->setVisible ( true );
         istate++;
@@ -689,12 +692,11 @@ namespace Hurricane {
 
   void  CellViewer::openHistoryCell ()
   {
-    QAction* historyAction = qobject_cast<QAction*> ( sender() );
-    if ( historyAction ) {
+    QAction* historyAction = qobject_cast<QAction*>( sender() );
+    if (historyAction) {
       list< shared_ptr<CellWidget::State> >::iterator  istate = _cellHistory.begin();
-    //size_t index = historyAction->data().toUInt();
-    //for ( ; index>0 ; index--, istate++ )
-    //  cerr << "History: " << (*istate)->getName() << endl;
+      size_t index = historyAction->data().toUInt();
+      for ( ; index>0 ; index--, ++istate );
       emit stateChanged ( *istate );
     }
   }
diff --git a/hurricane/src/viewer/CellWidget.cpp b/hurricane/src/viewer/CellWidget.cpp
index 8981c15e..4a4a99d9 100644
--- a/hurricane/src/viewer/CellWidget.cpp
+++ b/hurricane/src/viewer/CellWidget.cpp
@@ -977,6 +977,7 @@ namespace Hurricane {
     State* clone = new State();
 
     clone->setCell               ( getCell() );
+    clone->setTopPath            ( getTopPath() );
     clone->setCursorStep         ( getCursorStep() );
     clone->setUnitPower          ( getUnitPower() );
     clone->setDbuMode            ( getDbuMode() );
@@ -1173,6 +1174,12 @@ namespace Hurricane {
   }
 
 
+  void  CellWidget::resetCommands ()
+  {
+    for ( size_t i=0 ; i<_commands.size() ; ++i ) _commands[i]->reset();
+  }
+
+
   void  CellWidget::pushCursor ( Qt::CursorShape cursor )
   {
     setCursor ( cursor );
@@ -2410,39 +2417,46 @@ namespace Hurricane {
   }
 
 
-  void  CellWidget::setCell ( Cell* cell )
+  void  CellWidget::setCell ( Cell* cell, Path topPath, unsigned int flags )
   {
   //cerr << "CellWidget::setCell() - " << cell << endl;
 
-    if ( cell == getCell() ) return;
+    if (cell == getCell()) return;
 
-    openRefreshSession ();
+    if (not topPath.isEmpty() and (topPath.getTailInstance()->getMasterCell() != cell)) {
+      cerr << Warning( "CellWidget::setCell(): Incompatible Path %s with %s."
+                     , topPath.getCompactString().c_str()
+                     , getString(cell->getName()).c_str() ) << endl;
+      topPath = Path();
+    }
 
-    shared_ptr<State>  state ( new State(cell) );
-    setState ( state );
-    if ( cell and cell->isTerminal() ) setQueryFilter ( ~0 );
+    openRefreshSession();
+
+    shared_ptr<State>  state ( new State(cell,topPath) );
+    setState( state, flags );
+    if ( cell and cell->isTerminal() ) setQueryFilter( ~0 );
   //setRealMode ();
 
-    fitToContents ( false );
+    fitToContents( false );
 
-    _state->setHistoryEnable ( true );
+    _state->setHistoryEnable( true );
 
-    closeRefreshSession ();
+    closeRefreshSession();
   }
 
 
-  void  CellWidget::setState ( shared_ptr<State>& state )
+  void  CellWidget::setState ( shared_ptr<State>& state, unsigned int flags )
   {
   //cerr << "CellWidget::setState() - " << state->getName() << endl;
 
-    if ( state == _state ) return;
+    if (state == _state) return;
 
-    openRefreshSession ();
-
-    cellPreModificate ();
-    _state->getSelection  ().clear ();
-    _state->setCellWidget ( NULL );
-    _state->setTopLeft    ( getTopLeft() ); 
+    openRefreshSession();
+    cellPreModificate();
+    if (not (flags & NoResetCommands)) resetCommands();
+    _state->getSelection ().clear ();
+    _state->setCellWidget( NULL );
+    _state->setTopLeft   ( getTopLeft() ); 
 
     _cellChanged = true;
     _state       = state;
@@ -2453,23 +2467,22 @@ namespace Hurricane {
 //          << DbU::getValueString(_state->getTopLeft().getX()) << ","
 //          << DbU::getValueString(_state->getTopLeft().getY()) << ")" << endl;
 
-    _state->setHistoryEnable ( false );
-    _state->setCellWidget ( this );
-    _drawingQuery    .setCell       ( getCell() );
-    _drawingQuery    .setStartLevel ( _state->getStartLevel() );
-    _drawingQuery    .setStopLevel  ( _state->getStopLevel() );
-    _textDrawingQuery.setCell       ( getCell() );
+    _state->setHistoryEnable( false );
+    _state->setCellWidget   ( this );
+    _drawingQuery    .setCell      ( getCell() );
+    _drawingQuery    .setStartLevel( _state->getStartLevel() );
+    _drawingQuery    .setStopLevel ( _state->getStopLevel() );
+    _textDrawingQuery.setCell      ( getCell() );
 
-    reframe ();
-    _state->setHistoryEnable ( true );
+    reframe();
+    _state->setHistoryEnable( true );
 
-    emit cellChanged        ( getCell() );
-    emit stateChanged       ( _state );
-    emit queryFilterChanged ();
+    emit cellChanged       ( getCell() );
+    emit stateChanged      ( _state );
+    emit queryFilterChanged();
 
-    cellPostModificate ();
-
-    closeRefreshSession ();
+    cellPostModificate();
+    closeRefreshSession();
   }
 
 
diff --git a/hurricane/src/viewer/Command.cpp b/hurricane/src/viewer/Command.cpp
index f7949edb..271f311f 100644
--- a/hurricane/src/viewer/Command.cpp
+++ b/hurricane/src/viewer/Command.cpp
@@ -1,32 +1,22 @@
-
 // -*- C++ -*-
 //
 // This file is part of the Coriolis Software.
-// Copyright (c) UPMC/LIP6 2008-2015, All Rights Reserved
+// Copyright (c) UPMC 2008-2015, All Rights Reserved
 //
-// ===================================================================
-//
-// $Id$
-//
-// x-----------------------------------------------------------------x 
-// |                                                                 |
+// +-----------------------------------------------------------------+ 
 // |                  H U R R I C A N E                              |
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Module  :       "./Command.cpp"                            |
-// | *************************************************************** |
-// |  U p d a t e s                                                  |
-// |                                                                 |
-// x-----------------------------------------------------------------x
+// +-----------------------------------------------------------------+
 
 
 #include <QKeyEvent>
 #include <QMouseEvent>
 #include <QWheelEvent>
-
 #include <hurricane/viewer/CellWidget.h>
 #include <hurricane/viewer/Command.h>
 
@@ -68,6 +58,7 @@ namespace Hurricane {
   void  Command::mousePressEvent   ( QMouseEvent* ) { }
   void  Command::mouseReleaseEvent ( QMouseEvent* ) { }
   void  Command::draw              ()               { }
+  void  Command::reset             ()               { }
 
 
 } // End of Hurricane namespace.
diff --git a/hurricane/src/viewer/ControllerWidget.cpp b/hurricane/src/viewer/ControllerWidget.cpp
index ad15f900..d657919e 100644
--- a/hurricane/src/viewer/ControllerWidget.cpp
+++ b/hurricane/src/viewer/ControllerWidget.cpp
@@ -8,7 +8,7 @@
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Module  :       "./ControllerWidget.cpp"                   |
 // +-----------------------------------------------------------------+
@@ -30,6 +30,7 @@
 #include  <hurricane/viewer/PaletteWidget.h>
 #include  <hurricane/viewer/DisplayFilterWidget.h>
 #include  <hurricane/viewer/NetlistWidget.h>
+#include  <hurricane/viewer/HierarchyWidget.h>
 #include  <hurricane/viewer/SelectionWidget.h>
 #include  <hurricane/viewer/InspectorWidget.h>
 #include  <hurricane/viewer/ControllerWidget.h>
@@ -267,6 +268,62 @@ namespace Hurricane {
   }
 
 
+// -------------------------------------------------------------------
+// Class  :  "Hurricane::TabNetlist".
+
+
+  TabHierarchy::TabHierarchy ( QWidget* parent )
+    : ControllerTab         (parent)
+    , _hierarchyBrowser     (new HierarchyWidget())
+  {
+    _hierarchyBrowser->setObjectName ( "controller.tabHierarchy.hierarchyBrowser" );
+
+    QVBoxLayout* wLayout  = new QVBoxLayout ();
+    wLayout->setContentsMargins ( 10, 0, 10, 0 );
+    wLayout->setSpacing ( 0 );
+
+    QFrame* separator = new QFrame ();
+    separator->setFrameShape  ( QFrame::HLine );
+    separator->setFrameShadow ( QFrame::Sunken );
+    wLayout->addWidget ( separator );
+    wLayout->addWidget ( _hierarchyBrowser );
+
+    setLayout ( wLayout );
+  }
+
+
+  void  TabHierarchy::setCell ( Cell* cell )
+  { }
+
+
+  void  TabHierarchy::setCellWidget ( CellWidget* cellWidget )
+  {
+    if (getCellWidget() != cellWidget) {
+      ControllerTab::setCellWidget( cellWidget );
+      _hierarchyBrowser->setCellWidget( cellWidget );
+      if (getCellWidget()) {
+        connect( getCellWidget(), SIGNAL(cellChanged(Cell*)), this, SLOT(setCell(Cell*)) );
+      }
+    }
+  }
+
+
+  void  TabHierarchy::cellPreModificate ()
+  { }
+
+
+  void  TabHierarchy::cellPostModificate ()
+  {
+    CellWidget* cw      = getCellWidget();
+    Cell*       topCell = cw->getTopCell();
+    if (not topCell) topCell = cw->getCell();
+    _hierarchyBrowser->setCell( topCell );
+
+    if (not cw->getTopPath().isEmpty())
+      _hierarchyBrowser->rexpand( cw->getTopPath() );
+  }
+
+
 // -------------------------------------------------------------------
 // Class  :  "Hurricane::TabSelection".
 
@@ -475,48 +532,51 @@ namespace Hurricane {
     , _tabPalette      (new TabPalette())
     , _tabDisplayFilter(new TabDisplayFilter())
     , _tabNetlist      (new TabNetlist())
+    , _tabHierarchy    (new TabHierarchy())
     , _tabSelection    (new TabSelection())
     , _tabInspector    (new TabInspector())
     , _tabSettings     (new TabSettings())
   {
-    setObjectName  ( "controller" );
-    setAttribute   ( Qt::WA_QuitOnClose, false );
-    setWindowTitle ( tr("Controller") );
+    setObjectName ( "controller" );
+    setAttribute  ( Qt::WA_QuitOnClose, false );
+    setWindowTitle( tr("Controller") );
 
   //connect ( _netlistBrowser, SIGNAL(destroyed()), this, SLOT(netlistBrowserDestroyed()) );
 
-    _tabGraphics     ->setObjectName ( "controller.graphics"      );
-    _tabPalette      ->setObjectName ( "controller.palette"       );
-    _tabDisplayFilter->setObjectName ( "controller.displayFilter" );
-    _tabNetlist      ->setObjectName ( "controller.tabNetlist"    );
-    _tabSelection    ->setObjectName ( "controller.tabSelection"  );
-    _tabInspector    ->setObjectName ( "controller.tabInspector"  );
-    _tabSettings     ->setObjectName ( "controller.tabSettings"  );
+    _tabGraphics     ->setObjectName( "controller.graphics"      );
+    _tabPalette      ->setObjectName( "controller.palette"       );
+    _tabDisplayFilter->setObjectName( "controller.displayFilter" );
+    _tabNetlist      ->setObjectName( "controller.tabNetlist"    );
+    _tabHierarchy    ->setObjectName( "controller.tabHierarchy"  );
+    _tabSelection    ->setObjectName( "controller.tabSelection"  );
+    _tabInspector    ->setObjectName( "controller.tabInspector"  );
+    _tabSettings     ->setObjectName( "controller.tabSettings"   );
 
-    addTab ( _tabGraphics      , "Look"        );
-    addTab ( _tabDisplayFilter , "Filter"      );
-    addTab ( _tabPalette       , "Layers&&Gos" );
-    addTab ( _tabNetlist       , "Netlist"     );
-    addTab ( _tabSelection     , "Selection"   );
-    addTab ( _tabInspector     , "Inspector"   );
-    addTab ( _tabSettings      , "Settings"    );
+    addTab( _tabGraphics      , "Look"        );
+    addTab( _tabDisplayFilter , "Filter"      );
+    addTab( _tabPalette       , "Layers&&Gos" );
+    addTab( _tabHierarchy     , "Hierarchy"   );
+    addTab( _tabNetlist       , "Netlist"     );
+    addTab( _tabSelection     , "Selection"   );
+    addTab( _tabInspector     , "Inspector"   );
+    addTab( _tabSettings      , "Settings"    );
 
     QAction* toggleShow = new QAction ( tr("Controller"), this );
-    toggleShow->setObjectName ( "controller.action.hideShow" );
-    toggleShow->setShortcut   ( QKeySequence(tr("CTRL+I")) );
-    addAction ( toggleShow );
+    toggleShow->setObjectName( "controller.action.hideShow" );
+    toggleShow->setShortcut  ( QKeySequence(tr("CTRL+I")) );
+    addAction( toggleShow );
 
-    connect ( toggleShow, SIGNAL(triggered())        , this, SLOT(toggleShow()) );
-    connect ( this      , SIGNAL(currentChanged(int)), this, SLOT(updateTab(int)) );
-    connect ( _tabSelection->getSelection(), SIGNAL(inspect(Occurrence&))
-            , _tabInspector                , SLOT  (setSelectionOccurrence(Occurrence&)) );
+    connect( toggleShow, SIGNAL(triggered())        , this, SLOT(toggleShow()) );
+    connect( this      , SIGNAL(currentChanged(int)), this, SLOT(updateTab(int)) );
+    connect( _tabSelection->getSelection(), SIGNAL(inspect(Occurrence&))
+           , _tabInspector                , SLOT  (setSelectionOccurrence(Occurrence&)) );
                                         
-    resize ( Graphics::toHighDpi(600), Graphics::toHighDpi(500) );
+    resize( Graphics::toHighDpi(600), Graphics::toHighDpi(500) );
   }
 
 
   void  ControllerWidget::toggleShow ()
-  { setVisible ( !isVisible() ); }
+  { setVisible( !isVisible() ); }
 
 
   void  ControllerWidget::setCellWidget ( CellWidget* cellWidget )
diff --git a/hurricane/src/viewer/HierarchyCommand.cpp b/hurricane/src/viewer/HierarchyCommand.cpp
index bc66dfa2..179e5d08 100644
--- a/hurricane/src/viewer/HierarchyCommand.cpp
+++ b/hurricane/src/viewer/HierarchyCommand.cpp
@@ -1,26 +1,17 @@
-
 // -*- C++ -*-
 //
 // This file is part of the Coriolis Software.
-// Copyright (c) UPMC/LIP6 2008-2015, All Rights Reserved
+// Copyright (c) UPMC 2008-2015, All Rights Reserved
 //
-// ===================================================================
-//
-// $Id$
-//
-// x-----------------------------------------------------------------x 
-// |                                                                 |
+// +-----------------------------------------------------------------+ 
 // |                  H U R R I C A N E                              |
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Module  :       "./HierarchyCommand.cpp"                   |
-// | *************************************************************** |
-// |  U p d a t e s                                                  |
-// |                                                                 |
-// x-----------------------------------------------------------------x
+// +-----------------------------------------------------------------+
 
 
 # include <QMouseEvent>
@@ -58,41 +49,53 @@ namespace Hurricane {
   { return _name; }
 
 
+  void  HierarchyCommand::reset ()
+  {
+    _history.clear();
+    _historyIndex = 0;
+  }
+
+
   void  HierarchyCommand::keyReleaseEvent ( QKeyEvent* event )
   {
     bool  control = (event->modifiers() & Qt::ControlModifier);
     bool  shift   = (event->modifiers() & Qt::ShiftModifier  );
 
-    if ( !shift && !control ) return;
-    if ( !_cellWidget->getCell() ) return;
+    if (not shift and not control) return;
+    if (not _cellWidget->getCell()) return;
 
     QPoint position ( _cellWidget->mapFromGlobal(QCursor::pos()) );
     Box    pointBox ( _cellWidget->screenToDbuBox(QRect(position,QSize(1,1))) );
 
     switch ( event->key() ) {
       case Qt::Key_Up:
-        if ( ( _historyIndex > 0 ) && (shift || control) ) {
-          _cellWidget->setState ( _history[--_historyIndex]._state );
+        if ( (_historyIndex > 0) and (shift or control) ) {
+          _cellWidget->setState ( _history[--_historyIndex], CellWidget::NoResetCommands );
         }
         break;
       case Qt::Key_Down:
         {
-          if ( control ) {
-            if ( _history.empty() )
-              _history.push_back ( HistoryEntry ( NULL, _cellWidget->getState() ) );
+          if (control) {
+            Path topPath;
+            if (_history.empty()) {
+              _history.push_back( _cellWidget->getState() );
+              topPath = _cellWidget->getState()->getTopPath();
+            } else if (_historyIndex > 0) {
+              topPath = _history[_historyIndex-1]->getTopPath();
+            }
 
-            Instances instances = _cellWidget->getCell()->getInstancesUnder ( pointBox );
-            if ( !instances.isEmpty() ) {
-              _history.erase ( _history.begin()+_historyIndex+1, _history.end() );
+            Instances instances = _cellWidget->getCell()->getInstancesUnder( pointBox );
+            if (not instances.isEmpty()) {
+              _history.erase( _history.begin()+_historyIndex+1, _history.end() );
 
-              Instance* instance = instances.getFirst ();
-              _cellWidget->setCell ( instance->getMasterCell() );
-              _history.push_back ( HistoryEntry ( instance, _cellWidget->getState() ) );
+              topPath = Path( topPath, instances.getFirst() );
+              _cellWidget->setCell( topPath.getMasterCell(), topPath, CellWidget::NoResetCommands );
+              _history.push_back( _cellWidget->getState() );
               _historyIndex++;
             }
-          } else if ( shift ) {
-            if ( _historyIndex+1 < _history.size() ) {
-              _cellWidget->setState ( _history[++_historyIndex]._state );
+          } else if (shift) {
+            if (_historyIndex+1 < _history.size()) {
+              _cellWidget->setState( _history[++_historyIndex], CellWidget::NoResetCommands );
             }
           }
         }
diff --git a/hurricane/src/viewer/HierarchyInformations.cpp b/hurricane/src/viewer/HierarchyInformations.cpp
new file mode 100644
index 00000000..4a8a31fb
--- /dev/null
+++ b/hurricane/src/viewer/HierarchyInformations.cpp
@@ -0,0 +1,288 @@
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Module  :  "./HierarchyInformations.cpp"                   |
+// +-----------------------------------------------------------------+
+
+
+#include <QObject>
+#include "hurricane/Name.h"
+#include "hurricane/Cell.h"
+#include "hurricane/Instance.h"
+#include "hurricane/viewer/HierarchyInformations.h"
+
+
+namespace Hurricane {
+
+
+// -------------------------------------------------------------------
+// Class  :  "HierarchyInfos"
+
+  HierarchyInfos::HierarchyInfos ( HierarchyInfos* parent, size_t rowInParent )
+    : _parent     (parent)
+    , _rowInParent(rowInParent)
+  { }
+
+
+  HierarchyInfos::~HierarchyInfos ()
+  { }
+
+
+  int  HierarchyInfos::getColumnCount ()
+  { return 2; }
+
+
+  QVariant  HierarchyInfos::getColumnName ( int column )
+  {
+    switch ( column ) {
+      case 0: return QVariant(QObject::tr("Instance"));
+      case 1: return QVariant(QObject::tr("Model/Cell"));
+    }
+    return QVariant(QObject::tr("Column Out of Bound"));
+  }
+
+
+  QVariant  HierarchyInfos::getColumn ( int column ) const
+  {
+    if (isRoot()) return QVariant(QObject::tr("RootItem"));
+
+    const Instance* instance = getInstance();
+    if (instance) {
+      switch ( column ) {
+        case 0: return getString(instance->getName()).c_str();
+        case 1: return getString(instance->getMasterCell()->getName()).c_str();
+      }
+    } else {
+      switch ( column ) {
+        case 0: return "<Top Cell>";
+        case 1: return getString(getMasterCell()->getName()).c_str();
+      }
+    }
+
+    return QVariant(QObject::tr("Column Out of Bound"));
+  }
+
+
+  Path  HierarchyInfos::getPath () const
+  {
+    if (isRoot() or not getInstance()) return Path();
+
+    return Path( getParent()->getPath(), const_cast<Instance*>(getInstance()) );
+  }
+
+
+// -------------------------------------------------------------------
+// Class  :  "LeafHierarchyInfos"
+
+
+  const vector<HierarchyInfos*>  LeafHierarchyInfos::_instances;
+
+
+  LeafHierarchyInfos::LeafHierarchyInfos ( const Instance* instance
+                                         , HierarchyInfos* parent
+                                         , size_t          rowInParent )
+    : HierarchyInfos(parent,rowInParent)
+    , _instance(instance)
+  { }
+
+
+  LeafHierarchyInfos::~LeafHierarchyInfos ()
+  { }
+
+
+  bool                                LeafHierarchyInfos::isRoot           () const { return false; }
+  bool                                LeafHierarchyInfos::isLeaf           () const { return true; }
+  bool                                LeafHierarchyInfos::isCollapsed      () const { return true; }
+  const HierarchyInfos*               LeafHierarchyInfos::getRow           ( int row ) const { return NULL; }
+  int                                 LeafHierarchyInfos::size             () const { return 0; }
+  Cell*                               LeafHierarchyInfos::getMasterCell    () const { return _instance->getMasterCell(); }
+  const Instance*                     LeafHierarchyInfos::getInstance      () const { return _instance; }
+  const std::vector<HierarchyInfos*>& LeafHierarchyInfos::getInstances     () const { return _instances; }
+  QString                             LeafHierarchyInfos::getFilterPattern () const { return "<Not avalaible for leaf instances>"; }
+  void                                LeafHierarchyInfos::setFilterPattern ( const QString& ) { }
+  void                                LeafHierarchyInfos::expand           () { }
+  void                                LeafHierarchyInfos::collapse         () { }
+
+
+// -------------------------------------------------------------------
+// Class  :  "InstHierarchyInfos"
+
+  InstHierarchyInfos::InstHierarchyInfos ( const Instance* instance
+                                         , HierarchyInfos* parent
+                                         , size_t          rowInParent )
+    : HierarchyInfos(parent,rowInParent)
+    , _flags    (HierarchyInfos::Collapsed)
+    , _instance (instance)
+    , _instances()
+  { }
+
+
+  InstHierarchyInfos::~InstHierarchyInfos ()
+  {
+    collapse();
+  }
+
+
+  bool                                InstHierarchyInfos::isRoot           () const { return false; }
+  bool                                InstHierarchyInfos::isLeaf           () const { return false; }
+  bool                                InstHierarchyInfos::isCollapsed      () const { return _flags & HierarchyInfos::Collapsed; }
+  Cell*                               InstHierarchyInfos::getMasterCell    () const { return _instance->getMasterCell(); }
+  const Instance*                     InstHierarchyInfos::getInstance      () const { return _instance; }
+  const std::vector<HierarchyInfos*>& InstHierarchyInfos::getInstances     () const { return _instances; }
+  QString                             InstHierarchyInfos::getFilterPattern () const { return _filter.pattern(); }
+
+
+  int  InstHierarchyInfos::size () const
+  {
+    if (_flags & HierarchyInfos::Collapsed) {
+      const_cast<InstHierarchyInfos*>(this)->expand();
+    }
+    return _instances.size();
+  }
+
+
+  void  InstHierarchyInfos::setFilterPattern ( const QString& pattern )
+  {
+    _filter.setPattern( pattern );
+
+    if (_flags & HierarchyInfos::Collapsed) return;
+
+    size_t i = 0;
+    for ( Instance* instance : getMasterCell()->getInstances() ) {
+      if (instance->getMasterCell()->isFeed()) continue;
+
+      if ( (i < _instances.size()) and (instance == _instances[i]->getInstance()) ) {
+      // The instance *is already* in the list.
+        if ( not _filter.isEmpty() and (_filter.indexIn(getString(instance->getName()).c_str()) < 0) ) {
+          delete _instances[i];
+          _instances.erase( _instances.begin()+i );
+        } else {
+          ++i;
+        }
+      } else {
+      // The instance *is not* in the list.
+        if (_filter.isEmpty() or (_filter.indexIn(getString(instance->getName()).c_str()) >= 0) ) {
+          HierarchyInfos* infos = NULL;
+          if (instance->isLeaf()) infos = new LeafHierarchyInfos( instance, this, 0 );
+          else                    infos = new InstHierarchyInfos( instance, this, 0 );
+
+          _instances.insert( _instances.begin()+i, infos );
+          ++i;
+        }
+      }
+    }
+
+    for ( size_t i=0 ; i<_instances.size() ; ++i ) _instances[i]->setRowInParent( i );
+  }
+
+
+  void  InstHierarchyInfos::expand ()
+  {
+    if (not (_flags & HierarchyInfos::Collapsed)) return;
+    _flags &= ~HierarchyInfos::Collapsed;
+
+    if (not getMasterCell()) return;
+
+    for ( Instance* instance : getMasterCell()->getInstances() ) {
+      if (instance->getMasterCell()->isFeed()) continue;
+      if (not _filter.isEmpty()) {
+        if (_filter.indexIn(getString(instance->getName()).c_str()) < 0) continue;
+      }
+
+      HierarchyInfos* infos = NULL;
+      if (instance->isLeaf()) infos = new LeafHierarchyInfos( instance, this, _instances.size() );
+      else                    infos = new InstHierarchyInfos( instance, this, _instances.size() );
+
+      _instances.push_back( infos );
+    }
+  }
+
+
+  void  InstHierarchyInfos::collapse ()
+  {
+    if (_flags & HierarchyInfos::Collapsed) return;
+    _flags |= HierarchyInfos::Collapsed;
+
+    for ( HierarchyInfos* info : _instances ) delete info;
+
+    vector<HierarchyInfos*>().swap( _instances );
+  }
+
+
+  const HierarchyInfos* InstHierarchyInfos::getRow ( int row ) const
+  {
+    if (_flags & HierarchyInfos::Collapsed) {
+      const_cast<InstHierarchyInfos*>(this)->expand();
+    }
+
+    if (row >= (int)_instances.size()) return NULL;
+    return _instances[row];
+  }
+
+
+// -------------------------------------------------------------------
+// Class  :  "TopCellHierarchyInfos"
+
+  TopCellHierarchyInfos::TopCellHierarchyInfos ( Cell* cell, HierarchyInfos* parent )
+    : InstHierarchyInfos(NULL,parent,0)
+    , _rootCell(cell)
+  { expand(); }
+
+
+  TopCellHierarchyInfos::~TopCellHierarchyInfos ()
+  { collapse(); }
+
+
+  bool            TopCellHierarchyInfos::isRoot         () const { return false; }
+  Cell*           TopCellHierarchyInfos::getMasterCell  () const { return _rootCell; }
+  const Instance* TopCellHierarchyInfos::getInstance    () const { return NULL; }
+
+
+  void  TopCellHierarchyInfos::setCell ( Cell* rootCell )
+  {
+    collapse();
+    _rootCell = rootCell;
+    expand();
+  }
+
+
+// -------------------------------------------------------------------
+// Class  :  "RootHierarchyInfos"
+
+
+  RootHierarchyInfos::RootHierarchyInfos ( Cell* cell )
+    : HierarchyInfos(NULL,0)
+    , _instances()
+  {
+    _instances.push_back( new TopCellHierarchyInfos(cell,this) );
+  }
+
+
+  RootHierarchyInfos::~RootHierarchyInfos ()
+  { delete _instances[0]; }
+
+
+  bool                                RootHierarchyInfos::isRoot           () const { return true; }
+  bool                                RootHierarchyInfos::isLeaf           () const { return false; }
+  bool                                RootHierarchyInfos::isCollapsed      () const { return false; }
+  int                                 RootHierarchyInfos::size             () const { return _instances.size(); }
+  const HierarchyInfos*               RootHierarchyInfos::getRow           ( int row ) const { return (row==0) ? _instances[0] : NULL; }
+  Cell*                               RootHierarchyInfos::getMasterCell    () const { return _instances[0]->getMasterCell(); }
+  const Instance*                     RootHierarchyInfos::getInstance      () const { return NULL; }
+  const std::vector<HierarchyInfos*>& RootHierarchyInfos::getInstances     () const { return _instances; }
+  QString                             RootHierarchyInfos::getFilterPattern () const { return "<Not avalaible for Root>"; }
+  void                                RootHierarchyInfos::setFilterPattern ( const QString& ) { }
+  void                                RootHierarchyInfos::expand           () { }
+  void                                RootHierarchyInfos::collapse         () { }
+  void                                RootHierarchyInfos::setCell          ( Cell* topCell ) { dynamic_cast<TopCellHierarchyInfos*>(_instances[0])->setCell(topCell); }
+
+} // End of Hurricane namespace.
diff --git a/hurricane/src/viewer/HierarchyModel.cpp b/hurricane/src/viewer/HierarchyModel.cpp
new file mode 100644
index 00000000..2dd8bf60
--- /dev/null
+++ b/hurricane/src/viewer/HierarchyModel.cpp
@@ -0,0 +1,146 @@
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Module  :       "./HierarchyModel.cpp"                     |
+// +-----------------------------------------------------------------+
+
+
+#include <QFont>
+#include <QApplication>
+#include "hurricane/Name.h"
+#include "hurricane/Net.h"
+#include "hurricane/Cell.h"
+#include "hurricane/viewer/Graphics.h"
+#include "hurricane/viewer/HierarchyInformations.h"
+#include "hurricane/viewer/HierarchyModel.h"
+
+
+namespace Hurricane {
+
+
+  HierarchyModel::HierarchyModel ( QObject* parent )
+    : QAbstractItemModel(parent)
+    , _root             (NULL)
+  { }
+
+
+  HierarchyModel::~HierarchyModel ()
+  { }
+
+
+  bool  HierarchyModel::hasChildren ( const QModelIndex& parent ) const
+  {
+    if (not parent.isValid()) return true;
+
+    const HierarchyInfos* infos = infosFromIndex(parent);
+    if (not infos) return true;
+
+    return not infos->isLeaf();
+  }
+
+
+  QVariant  HierarchyModel::data ( const QModelIndex& index, int role ) const
+  {
+    static QFont nameFont  = Graphics::getFixedFont( QFont::Bold );
+    static QFont valueFont = Graphics::getFixedFont( QFont::Normal, true );
+
+    if (role == Qt::FontRole) {
+      switch (index.column()) {
+        case 0:  return nameFont;
+        default: return valueFont;
+      }
+      return QVariant();
+    }
+
+    if (not index.isValid()) return QVariant();
+
+    if (role == Qt::DisplayRole) {
+      const HierarchyInfos* infos = infosFromIndex( index );
+      if (infos)
+        return infos->getColumn( index.column() );
+    }
+    return QVariant();
+  }
+
+
+  QVariant  HierarchyModel::headerData ( int             section
+                                       , Qt::Orientation orientation
+                                       , int             role ) const
+  {
+    if (orientation == Qt::Vertical) return QVariant();
+
+    static QFont headerFont = Graphics::getFixedFont( QFont::Bold, false, false, +0 );
+
+    if (role == Qt::FontRole    ) return headerFont;
+    if (role != Qt::DisplayRole ) return QVariant();
+    if (role == Qt::SizeHintRole) return (Graphics::isHighDpi()) ? 600 : 300;
+
+    return HierarchyInfos::getColumnName( section );
+  }
+
+
+  int  HierarchyModel::rowCount ( const QModelIndex& parent ) const
+  {
+    const HierarchyInfos* infos = infosFromIndex( parent );
+    if (not infos) return 0;
+
+    if (infos->isCollapsed()) {
+      cerr << "HierarchyModel::rowCount(): collapsed " << infos->size() << " " << infos->getInstance() << endl; 
+    }
+
+    return infos->size();
+  }
+
+
+  int  HierarchyModel::columnCount ( const QModelIndex& parent ) const
+  { return _root.getColumnCount(); }
+
+
+  QModelIndex  HierarchyModel::index ( int row, int column, const QModelIndex& parent ) const
+  {
+    if (not _root.getMasterCell() or (row < 0) or (column < 0)) return QModelIndex();
+
+    const HierarchyInfos* parentInfos = infosFromIndex( parent );
+    const HierarchyInfos* childInfos  = parentInfos->getRow( row );
+
+    if (not childInfos) return QModelIndex();
+
+    QModelIndex index = createIndex( row, column, (void*)childInfos );
+    // cerr << "HierarchyModel::index(): " << index.row() << "+" << index.column()
+    //      << ":" << index.internalPointer()
+    //      << " " << childInfos->getMasterCell() << endl;
+
+    return index;
+  }
+
+
+  QModelIndex  HierarchyModel::parent ( const QModelIndex& child ) const
+  {
+    const HierarchyInfos* childInfos = infosFromIndex( child );
+    if (not childInfos) return QModelIndex();
+
+    const HierarchyInfos* parentInfos = childInfos->getParent();
+    if (not parentInfos) return QModelIndex();
+
+    const HierarchyInfos* grandParentInfos = parentInfos->getParent();
+    if (not grandParentInfos) return QModelIndex();
+
+    QModelIndex index = createIndex( parentInfos->getRowInParent(), 0, (void*)parentInfos );
+    // cerr << "HierarchyModel::index(): " << index.row() << "+" << index.column()
+    //      << ":" << index.internalPointer()
+    //      << " " << childInfos->getMasterCell() << endl;
+
+    return index;
+  }
+
+
+} // Hurricane namespace.
diff --git a/hurricane/src/viewer/HierarchyWidget.cpp b/hurricane/src/viewer/HierarchyWidget.cpp
new file mode 100644
index 00000000..b92cc485
--- /dev/null
+++ b/hurricane/src/viewer/HierarchyWidget.cpp
@@ -0,0 +1,265 @@
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC/LIP6 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Module  :       "./HierarchyWidget.cpp"                    |
+// +-----------------------------------------------------------------+
+
+
+#include <QFontMetrics>
+#include <QLabel>
+#include <QLineEdit>
+#include <QHeaderView>
+#include <QKeyEvent>
+#include <QGroupBox>
+#include <QVBoxLayout>
+#include <QAction>
+#include <QModelIndex>
+#include <QTreeView>
+#include "hurricane/Commons.h"
+#include "hurricane/Warning.h"
+#include "hurricane/Net.h"
+#include "hurricane/viewer/Graphics.h"
+#include "hurricane/viewer/HierarchyModel.h"
+#include "hurricane/viewer/HierarchyWidget.h"
+
+
+namespace Hurricane {
+
+
+// -------------------------------------------------------------------
+// Class  :  "HierarchyWidget".
+
+
+  HierarchyWidget::HierarchyWidget ( QWidget* parent )
+    : QWidget               (parent)
+    , _cellWidget           (NULL)
+    , _cell                 (NULL)
+    , _baseModel            (new HierarchyModel(this))
+    , _view                 (new QTreeView(this))
+    , _filterPatternLineEdit(new QLineEdit(this))
+    , _rowHeight            (20)
+  {
+    setAttribute( Qt::WA_DeleteOnClose );
+    setAttribute( Qt::WA_QuitOnClose, false );
+    setContextMenuPolicy( Qt::ActionsContextMenu );
+
+    _rowHeight = QFontMetrics( Graphics::getFixedFont() ).height() + 4;
+
+  //_view->setShowGrid            ( false );
+    _view->setAlternatingRowColors( true );
+    _view->setSelectionBehavior   ( QAbstractItemView::SelectRows );
+    _view->setSelectionMode       ( QAbstractItemView::SingleSelection );
+    _view->setSortingEnabled      ( true );
+    _view->setModel               ( _baseModel );
+  //_view->resizeColumnToContents ( 1 );
+
+    QHeaderView* horizontalHeader = _view->header();
+    horizontalHeader->setDefaultAlignment  ( Qt::AlignHCenter );
+    horizontalHeader->setMinimumSectionSize( (Graphics::isHighDpi()) ? 600 : 300 );
+    horizontalHeader->setResizeMode        ( 0, QHeaderView::Interactive );
+    horizontalHeader->setResizeMode        ( 1, QHeaderView::Interactive );
+    horizontalHeader->setStretchLastSection( true );
+
+    QLabel* filterPatternLabel = new QLabel(tr("&Filter pattern:"), this);
+    filterPatternLabel->setBuddy( _filterPatternLineEdit );
+
+    QGridLayout* gLayout = new QGridLayout();
+    gLayout->addWidget( _view                , 1, 0, 1, 2 );
+    gLayout->addWidget( filterPatternLabel   , 2, 0 );
+    gLayout->addWidget(_filterPatternLineEdit, 2, 1);
+
+    setLayout( gLayout );
+
+    connect ( _view, SIGNAL(collapsed   (const QModelIndex&))
+            , this , SLOT  (collapseHook(const QModelIndex& )) );                       
+    connect ( _filterPatternLineEdit , SIGNAL(returnPressed    ())
+            , this                   , SLOT  (textFilterChanged()) );                       
+    connect ( _view->selectionModel(), SIGNAL(selectionChanged(const QItemSelection&,const QItemSelection&))
+            , this                   , SLOT  (followSelected  (const QItemSelection&,const QItemSelection&)) );
+
+    TreeKeyFilter* filter = new TreeKeyFilter( this );
+    _view->installEventFilter( filter );
+
+    resize(300, 300);
+  }
+
+
+  void  HierarchyWidget::setCell ( Cell* cell )
+  {
+    if (_cell == cell) return;
+
+    _cell = cell;
+    _view->setVisible( false );
+    _view->selectionModel()->clear();
+    _baseModel->setCell( cell );
+     
+    string windowTitle = "Hierarchy" + getString(cell);
+    setWindowTitle( tr(windowTitle.c_str()) );
+
+    _view->selectionModel()->select( _baseModel->index(0,0,_view->rootIndex())
+                                   , QItemSelectionModel::Select|QItemSelectionModel::Rows );
+    _view->resizeColumnToContents( 0 );
+    _view->setVisible( true );
+  }
+
+
+  bool  HierarchyWidget::isRSelected ( const QModelIndex& index ) const
+  {
+    HierarchyInfos* infos = const_cast<HierarchyInfos*>(_baseModel->infosFromIndex(index));
+    for ( size_t row=0 ; row < infos->getInstances().size() ; ++row ) {
+      QModelIndex childIndex  = _baseModel->index( row, 0, index );
+      if (_view->selectionModel()->isSelected(childIndex)) 
+        return true;
+
+      if (not infos->isCollapsed() and isRSelected(childIndex)) return true;
+    }
+
+    return false;
+  }
+
+
+  void  HierarchyWidget::rexpand ( Path path )
+  {
+    if (path.isEmpty()) return;
+
+    QModelIndex index = _baseModel->index( 0, 0, QModelIndex() );
+    do {
+      Instance* head = path.getHeadInstance();
+      path = path.getTailPath();
+
+      _view->expand( index ); 
+      HierarchyInfos* parentInfos = const_cast<HierarchyInfos*>( _baseModel->infosFromIndex(index) );
+      HierarchyInfos* childInfos  = NULL;
+
+      for ( HierarchyInfos* child : parentInfos->getInstances() ) {
+        if (child->getInstance() == head) {
+          childInfos = child;
+          break;
+        }
+      }
+      if (not childInfos) {
+        cerr << Warning("HierarchyWidget::rexpand(): discrepency between Path and Hierarchy.") << endl;
+        return;
+      }
+
+      index = _baseModel->index( childInfos->getRowInParent(), 0, index );
+    } while (not path.isEmpty());
+
+    _view->selectionModel()->clear();
+    _view->selectionModel()->select( index, QItemSelectionModel::Select|QItemSelectionModel::Rows );
+    _view->setCurrentIndex( index );
+  }
+
+
+  void  HierarchyWidget::rexpand ( const QModelIndex& index )
+  {
+    HierarchyInfos* infos = const_cast<HierarchyInfos*>(_baseModel->infosFromIndex(index));
+    if (infos) {
+      if (not infos->isCollapsed()) {
+        _view->expand( index );
+        for ( HierarchyInfos* child : infos->getInstances() ) {
+          rexpand( _baseModel->index( child->getRowInParent(), 0, index ) );
+        }
+      }
+    }
+  }
+
+
+  void  HierarchyWidget::collapseHook ( const QModelIndex& index )
+  {
+    if (isRSelected(index)) {
+      _view->selectionModel()->clear();
+      _view->selectionModel()->select( index, QItemSelectionModel::Select|QItemSelectionModel::Rows );
+    }
+    
+    HierarchyInfos* infos = const_cast<HierarchyInfos*>(_baseModel->infosFromIndex(index));
+    infos->collapse();
+  }
+
+
+  void  HierarchyWidget::textFilterChanged ()
+  {
+    QModelIndexList selecteds = _view->selectionModel()->selectedIndexes();
+
+    if (not selecteds.isEmpty()) {
+      QModelIndex     index = selecteds[0];
+      HierarchyInfos* infos = const_cast<HierarchyInfos*>(_baseModel->infosFromIndex(index));
+      infos->setFilterPattern( _filterPatternLineEdit->text() );
+      _view->reset();
+      rexpand( _view->rootIndex() );
+      _view->selectionModel()->select( index, QItemSelectionModel::Select|QItemSelectionModel::Rows );
+      _view->setCurrentIndex( index );
+    }
+  }
+
+
+  void  HierarchyWidget::followSelected ( const QItemSelection& selecteds, const QItemSelection& deselecteds )
+  {
+    if (selecteds.indexes().isEmpty()) {
+    //cerr << Warning("HierarchyWidget::followSelected(): Selection should never be empty.") << endl;
+      return;
+    }
+
+    QModelIndex     index = selecteds.indexes()[0];
+    HierarchyInfos* infos = const_cast<HierarchyInfos*>(_baseModel->infosFromIndex(index));
+    _filterPatternLineEdit->setText( infos->getFilterPattern() );
+  }
+
+
+  void  HierarchyWidget::goTo ( int delta )
+  {
+    if (delta == 0) return;
+
+    QModelIndex newIndex = _baseModel->index( _view->currentIndex().row()+delta, 0, QModelIndex() );
+
+  //if (newIndex.isValid())
+  //  _view->selectRow( newIndex.row() );
+  }
+
+
+// -------------------------------------------------------------------
+// Class  :  "TreeKeyFilter".
+
+
+  TreeKeyFilter::TreeKeyFilter ( QObject* parent )
+    : QObject(parent)
+  { }
+
+
+  bool  TreeKeyFilter::eventFilter ( QObject* object, QEvent* event )
+  {
+    if (event->type() == QEvent::KeyPress) {
+      HierarchyWidget* owner = qobject_cast<HierarchyWidget*>( parent() );
+      if (not owner) return false;
+
+      QKeyEvent* keyEvent = static_cast<QKeyEvent*>(event);
+
+      if (keyEvent->key() == Qt::Key_Return) {
+        QModelIndexList selecteds = owner->_view->selectionModel()->selectedIndexes();
+
+        if (not selecteds.isEmpty()) {
+          QModelIndex     index = selecteds[0];
+          HierarchyInfos* infos = const_cast<HierarchyInfos*>(owner->_baseModel->infosFromIndex(index));
+          if (infos) {
+            if (owner->getCellWidget()) {
+              owner->getCellWidget()->setCell( infos->getMasterCell(), infos->getPath() );
+            }
+          }
+        }
+      }
+    }
+
+    return QObject::eventFilter( object, event );
+  }
+
+
+} // Hurricane namespace.
diff --git a/hurricane/src/viewer/hurricane/viewer/CellWidget.h b/hurricane/src/viewer/hurricane/viewer/CellWidget.h
index 2be1da63..69d9fc6f 100644
--- a/hurricane/src/viewer/hurricane/viewer/CellWidget.h
+++ b/hurricane/src/viewer/hurricane/viewer/CellWidget.h
@@ -97,15 +97,18 @@ namespace Hurricane {
       typedef void ( InitExtensionGo_t )( CellWidget* );
       typedef boost::function< void(QPainter&) >  PainterCb_t;
       enum    RubberShape    { Centric=1, Barycentric, Steiner };
-      enum    TextFlag       { Bold    =0x001
-                             , BigFont =0x002
-                             , Reverse =0x004
-                             , Frame   =0x008
-                             , Rounded =0x010
-                             , Center  =0x020
-                             , Left    =0x040
-                             , Right   =0x080
-                             , Top     =0x100
+      enum    TextFlag       { Bold    =0x0001
+                             , BigFont =0x0002
+                             , Reverse =0x0004
+                             , Frame   =0x0008
+                             , Rounded =0x0010
+                             , Center  =0x0020
+                             , Left    =0x0040
+                             , Right   =0x0080
+                             , Top     =0x0100
+                             };
+      enum    Flag           { NoFlags        =0x0000
+                             , NoResetCommands=0x0001
                              };
     public:
       enum    ResolutionMode { Res_CellMode=1, Res_DesignMode=2 };
@@ -115,8 +118,10 @@ namespace Hurricane {
       virtual                          ~CellWidget                 ();
     // Accessors.                                                  
     //        MapView*                  getMapView                 () { return _mapView; };
-              void                      setCell                    ( Cell* );
+              void                      setCell                    ( Cell*, Path  topPath=Path(), unsigned int flags=NoFlags );
       inline  Cell*                     getCell                    () const;
+      inline  Cell*                     getTopCell                 () const;
+      inline  Path                      getTopPath                 () const;
       inline  shared_ptr<State>&        getState                   ();
       inline  shared_ptr<State>         getStateClone              ();
       inline  PaletteWidget*            getPalette                 ();
@@ -132,6 +137,7 @@ namespace Hurricane {
               void                      detachFromPalette          ();
               void                      bindCommand                ( Command* );
               void                      unbindCommand              ( Command* );
+              void                      resetCommands              ();
       inline  void                      setActiveCommand           ( Command* );
       inline  Command*                  getActiveCommand           () const;
               Command*                  getCommand                 ( const std::string& ) const;
@@ -245,7 +251,8 @@ namespace Hurricane {
       virtual void                      paintEvent                 ( QPaintEvent* );
     public slots:                                                
     // Qt QWidget Slots Overload & CellWidget Specifics.         
-              void                      setState                   ( shared_ptr<CellWidget::State>& );
+              void                      setState                   ( shared_ptr<CellWidget::State>&
+                                                                   , unsigned int flags=NoFlags );
       inline  void                      openRefreshSession         ();
       inline  void                      closeRefreshSession        ();
       inline  DrawingPlanes&            getDrawingPlanes           ();
@@ -534,9 +541,10 @@ namespace Hurricane {
     public:
       class State {
         public:
-          inline                     State                  ( Cell* cell=NULL );
+          inline                     State                  ( Cell* cell=NULL, Path topPath=Path() );
                  State*              clone                  () const;
           inline void                setCell                ( Cell* );
+          inline void                setTopPath             ( Path );
           inline void                setCellWidget          ( CellWidget* );
           inline void                setCursorStep          ( DbU::Unit );
           inline DbU::Unit           getCursorStep          () const;
@@ -557,6 +565,8 @@ namespace Hurricane {
                  bool                scaleHistoryUp         ();
                  bool                scaleHistoryDown       ();
           inline Cell*               getCell                () const;
+          inline Cell*               getTopCell             () const;
+          inline Path                getTopPath             () const;
                  const Name&         getName                () const;
           inline SelectorCriterions& getSelection           ();
           inline RulerSet&           getRulers              ();
@@ -590,6 +600,7 @@ namespace Hurricane {
 
         private:
           Cell*               _cell;
+          Path                _topPath;
           CellWidget*         _cellWidget;
           SelectorCriterions  _selection;
           RulerSet            _rulers;
@@ -879,8 +890,9 @@ namespace Hurricane {
   { }
 
 
-  inline CellWidget::State::State ( Cell* cell )
+  inline CellWidget::State::State ( Cell* cell, Path topPath )
     : _cell               (cell)
+    , _topPath            (topPath)
     , _cellWidget         (NULL)
     , _selection          ()
     , _rulers             ()
@@ -922,6 +934,10 @@ namespace Hurricane {
   { _cell = cell; }
 
 
+  inline void  CellWidget::State::setTopPath ( Path topPath )
+  { _topPath = topPath; }
+
+
   inline void  CellWidget::State::setCellWidget ( CellWidget* cw )
   {
     _cellWidget = cw;
@@ -1002,6 +1018,14 @@ namespace Hurricane {
   { return _cell; }
 
 
+  inline Path  CellWidget::State::getTopPath () const
+  { return _topPath; }
+
+
+  inline Cell* CellWidget::State::getTopCell () const
+  { return (_topPath.isEmpty()) ? _cell : _topPath.getOwnerCell(); }
+
+
   inline DbU::Unit  CellWidget::State::cursorStep () const
   { return _cursorStep; }
 
@@ -1255,6 +1279,14 @@ namespace Hurricane {
   { return _state->getCell(); }
 
 
+  inline Cell* CellWidget::getTopCell () const
+  { return _state->getTopCell(); }
+
+
+  inline Path  CellWidget::getTopPath () const
+  { return _state->getTopPath(); }
+
+
   inline PaletteWidget* CellWidget::getPalette ()
   { return _palette; }
 
diff --git a/hurricane/src/viewer/hurricane/viewer/Command.h b/hurricane/src/viewer/hurricane/viewer/Command.h
index eef67714..b6296e3d 100644
--- a/hurricane/src/viewer/hurricane/viewer/Command.h
+++ b/hurricane/src/viewer/hurricane/viewer/Command.h
@@ -1,27 +1,24 @@
-
 // -*- C++ -*-
 //
 // This file is part of the Coriolis Software.
-// Copyright (c) UPMC/LIP6 2008-2012, All Rights Reserved
+// Copyright (c) UPMC 2008-2015, All Rights Reserved
 //
 // +-----------------------------------------------------------------+ 
 // |                  H U R R I C A N E                              |
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Header  :  "./hurricane/viewer/Command.h"                  |
 // +-----------------------------------------------------------------+
 
 
-#ifndef  __HURRICANE_COMMAND_H__
-#define  __HURRICANE_COMMAND_H__
-
-
-#include  <string>
-#include  <map>
+#ifndef  HURRICANE_COMMAND_H
+#define  HURRICANE_COMMAND_H
 
+#include <string>
+#include <map>
 
 class QKeyEvent;
 class QMouseEvent;
@@ -54,6 +51,7 @@ namespace Hurricane {
       virtual void          mousePressEvent   ( QMouseEvent* );
       virtual void          mouseReleaseEvent ( QMouseEvent* );
       virtual void          draw              ();
+      virtual void          reset             ();
     private:
                             Command           ( const Command& );
               Command&      operator=         ( const Command& );
diff --git a/hurricane/src/viewer/hurricane/viewer/ControllerWidget.h b/hurricane/src/viewer/hurricane/viewer/ControllerWidget.h
index be9f7873..ae95f958 100644
--- a/hurricane/src/viewer/hurricane/viewer/ControllerWidget.h
+++ b/hurricane/src/viewer/hurricane/viewer/ControllerWidget.h
@@ -9,7 +9,7 @@
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Header  :       "./hurricane/viewer/ControllerWidget.h"    |
 // +-----------------------------------------------------------------+
@@ -42,6 +42,7 @@ namespace Hurricane {
   class GraphicsWidget;
   class DisplayFilterWidget;
   class NetlistWidget;
+  class HierarchyWidget;
   class SelectionWidget;
   class InspectorWidget;
 
@@ -167,6 +168,30 @@ namespace Hurricane {
   inline QCheckBox*     TabNetlist::getSyncSelection  () { return _syncSelection; }
 
 
+// -------------------------------------------------------------------
+// Class  :  "Hurricane::TabHierarchy".
+
+
+  class TabHierarchy : public ControllerTab {
+      Q_OBJECT;
+
+    public:
+                               TabHierarchy        ( QWidget* parent=NULL );
+      inline  HierarchyWidget* getHierarchyBrowser ();
+      virtual void             cellPreModificate   ();
+      virtual void             cellPostModificate  ();
+    public slots:   
+      virtual void             setCell             ( Cell* );
+      virtual void             setCellWidget       ( CellWidget* );
+
+    protected:
+      HierarchyWidget* _hierarchyBrowser;
+  };
+
+
+  inline HierarchyWidget* TabHierarchy::getHierarchyBrowser () { return _hierarchyBrowser; }
+
+
 // -------------------------------------------------------------------
 // Class  :  "Hurricane::TabSelection".
 
@@ -268,23 +293,24 @@ namespace Hurricane {
       Q_OBJECT;
       
     public:
-                                  ControllerWidget   ( QWidget* parent=NULL );
-      inline CellWidget*          getCellWidget      ();
-      inline GraphicsWidget*      getGraphics        ();
-      inline PaletteWidget*       getPalette         ();
-      inline DisplayFilterWidget* getDisplayFilter   ();
-      inline NetlistWidget*       getNetlistBrowser  ();
-      inline SelectionWidget*     getSelection       ();
-      inline InspectorWidget*     getInspectorWidget ();
-      inline TabSettings*         getSettings        ();
-             void                 setCellWidget      ( CellWidget* );
-    //inline int                  addSetting         ( QWidget* page, const QString& label );
-    public slots:                 
-             void                 cellPreModificate  ();
-             void                 cellPostModificate ();
-             void                 cellChanged        ( Cell* );
-             void                 updateTab          ( int index );
-             void                 toggleShow         ();
+                                  ControllerWidget    ( QWidget* parent=NULL );
+      inline CellWidget*          getCellWidget       ();
+      inline GraphicsWidget*      getGraphics         ();
+      inline PaletteWidget*       getPalette          ();
+      inline DisplayFilterWidget* getDisplayFilter    ();
+      inline NetlistWidget*       getNetlistBrowser   ();
+      inline HierarchyWidget*     getHierarchyBrowser ();
+      inline SelectionWidget*     getSelection        ();
+      inline InspectorWidget*     getInspectorWidget  ();
+      inline TabSettings*         getSettings         ();
+             void                 setCellWidget       ( CellWidget* );
+    //inline int                  addSetting          ( QWidget* page, const QString& label );
+    public slots:                                     
+             void                 cellPreModificate   ();
+             void                 cellPostModificate  ();
+             void                 cellChanged         ( Cell* );
+             void                 updateTab           ( int index );
+             void                 toggleShow          ();
 
     protected:
       CellWidget*       _cellWidget;
@@ -292,21 +318,23 @@ namespace Hurricane {
       TabPalette*       _tabPalette;
       TabDisplayFilter* _tabDisplayFilter;
       TabNetlist*       _tabNetlist;
+      TabHierarchy*     _tabHierarchy;
       TabSelection*     _tabSelection;
       TabInspector*     _tabInspector;
       TabSettings*      _tabSettings;
   };
 
 
-  inline CellWidget*          ControllerWidget::getCellWidget      () { return _cellWidget; }
-  inline GraphicsWidget*      ControllerWidget::getGraphics        () { return _tabGraphics->getGraphics(); }
-  inline PaletteWidget*       ControllerWidget::getPalette         () { return _tabPalette->getPalette(); }
-  inline DisplayFilterWidget* ControllerWidget::getDisplayFilter   () { return _tabDisplayFilter->getDisplayFilter(); }
-  inline NetlistWidget*       ControllerWidget::getNetlistBrowser  () { return _tabNetlist->getNetlistBrowser(); }
-  inline SelectionWidget*     ControllerWidget::getSelection       () { return _tabSelection->getSelection(); }
-  inline InspectorWidget*     ControllerWidget::getInspectorWidget () { return _tabInspector->getInspectorWidget(); }
-  inline TabSettings*         ControllerWidget::getSettings        () { return _tabSettings; }
-//inline int                  ControllerWidget::addSetting         ( QWidget* page, const QString& label ) { return _tabSettings->addSetting(page,label); }
+  inline CellWidget*          ControllerWidget::getCellWidget       () { return _cellWidget; }
+  inline GraphicsWidget*      ControllerWidget::getGraphics         () { return _tabGraphics->getGraphics(); }
+  inline PaletteWidget*       ControllerWidget::getPalette          () { return _tabPalette->getPalette(); }
+  inline DisplayFilterWidget* ControllerWidget::getDisplayFilter    () { return _tabDisplayFilter->getDisplayFilter(); }
+  inline NetlistWidget*       ControllerWidget::getNetlistBrowser   () { return _tabNetlist->getNetlistBrowser(); }
+  inline HierarchyWidget*     ControllerWidget::getHierarchyBrowser () { return _tabHierarchy->getHierarchyBrowser(); }
+  inline SelectionWidget*     ControllerWidget::getSelection        () { return _tabSelection->getSelection(); }
+  inline InspectorWidget*     ControllerWidget::getInspectorWidget  () { return _tabInspector->getInspectorWidget(); }
+  inline TabSettings*         ControllerWidget::getSettings         () { return _tabSettings; }
+//inline int                  ControllerWidget::addSetting          ( QWidget* page, const QString& label ) { return _tabSettings->addSetting(page,label); }
 
 
 }  // End of Hurricane namespace.
diff --git a/hurricane/src/viewer/hurricane/viewer/HierarchyCommand.h b/hurricane/src/viewer/hurricane/viewer/HierarchyCommand.h
index db74882b..201063de 100644
--- a/hurricane/src/viewer/hurricane/viewer/HierarchyCommand.h
+++ b/hurricane/src/viewer/hurricane/viewer/HierarchyCommand.h
@@ -1,87 +1,55 @@
-
 // -*- C++ -*-
 //
 // This file is part of the Coriolis Software.
-// Copyright (c) UPMC/LIP6 2008-2015, All Rights Reserved
+// Copyright (c) UPMC 2008-2015, All Rights Reserved
 //
-// ===================================================================
-//
-// $Id$
-//
-// x-----------------------------------------------------------------x 
-// |                                                                 |
+// +-----------------------------------------------------------------+ 
 // |                  H U R R I C A N E                              |
 // |     V L S I   B a c k e n d   D a t a - B a s e                 |
 // |                                                                 |
 // |  Author      :                    Jean-Paul CHAPUT              |
-// |  E-mail      :       Jean-Paul.Chaput@asim.lip6.fr              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
 // | =============================================================== |
 // |  C++ Header  :       "./HierarchyCommand.h"                     |
-// | *************************************************************** |
-// |  U p d a t e s                                                  |
-// |                                                                 |
-// x-----------------------------------------------------------------x
+// +-----------------------------------------------------------------+
 
 
-#ifndef  __HURRICANE_HIERARCHY_COMMAND__
-#define  __HURRICANE_HIERARCHY_COMMAND__
-
-#include  <set>
-
-#include  <QObject>
-#include  <QPoint>
+#ifndef  HURRICANE_HIERARCHY_COMMAND_H
+#define  HURRICANE_HIERARCHY_COMMAND_H
 
+#include <set>
+#include <QObject>
+#include <QPoint>
 class QAction;
 
-#include  "hurricane/Occurrence.h"
-#include  "hurricane/viewer/Command.h"
-#include  "hurricane/viewer/CellWidget.h"
-
-
-using namespace std;
+#include "hurricane/Occurrence.h"
+#include "hurricane/viewer/Command.h"
+#include "hurricane/viewer/CellWidget.h"
 
 
 namespace Hurricane {
 
-
   class Cell;
 
 
   class HierarchyCommand : public Command {
     public:
-                                HierarchyCommand  ();
-      virtual                  ~HierarchyCommand  ();
-      virtual const string&     getName           () const;
-      virtual void              keyReleaseEvent   ( QKeyEvent* );
+                                  HierarchyCommand  ();
+      virtual                    ~HierarchyCommand  ();
+      virtual const std::string&  getName           () const;
+      virtual void                reset             ();
+      virtual void                keyReleaseEvent   ( QKeyEvent* );
     private:                  
-                                HierarchyCommand  ( const HierarchyCommand& );
-              HierarchyCommand& operator=         ( const HierarchyCommand& );
+                                  HierarchyCommand  ( const HierarchyCommand& );
+              HierarchyCommand&   operator=         ( const HierarchyCommand& );
 
     private:
-      class HistoryEntry {
-        public:
-          inline HistoryEntry ( Instance*, shared_ptr<CellWidget::State> );
-        public:
-          Instance*                      _instance;
-          shared_ptr<CellWidget::State>  _state;
-      };
-    private:
-      static string         _name;
-      vector<HistoryEntry>  _history;
-      size_t                _historyIndex;
+      static std::string                                 _name;
+      std::vector< std::shared_ptr<CellWidget::State> >  _history;
+      size_t                                             _historyIndex;
   };
 
 
-// Inline Functions.
-  inline HierarchyCommand::HistoryEntry::HistoryEntry  ( Instance*                     instance
-                                                       , shared_ptr<CellWidget::State> state
-                                                       )
-    : _instance(instance)
-    , _state   (state)
-  { }
+} // Hurricane namespace.
 
-
-} // End of Hurricane namespace.
-
-
-#endif
+#endif  // HURRICANE_HIERARCHY_COMMAND_H
diff --git a/hurricane/src/viewer/hurricane/viewer/HierarchyInformations.h b/hurricane/src/viewer/hurricane/viewer/HierarchyInformations.h
new file mode 100644
index 00000000..9a44cf11
--- /dev/null
+++ b/hurricane/src/viewer/hurricane/viewer/HierarchyInformations.h
@@ -0,0 +1,178 @@
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Header  :  "./hurricane/viewer/HierarchyInformations.h"    |
+// +-----------------------------------------------------------------+
+
+
+#ifndef  HURRICANE_HIERARCHY_INFORMATIONS_H
+#define  HURRICANE_HIERARCHY_INFORMATIONS_H
+
+#include <vector>
+#include <QRegExp>
+#include <QVariant>
+#include "hurricane/Commons.h"
+#include "hurricane/Path.h"
+
+
+namespace Hurricane {
+
+  class Instance;
+  class Cell;
+
+
+// -------------------------------------------------------------------
+// Class  :  "HierarchyInfos"
+
+
+  class HierarchyInfos {
+    public:
+      enum Flags { NoFlags=0x0000, Collapsed=0x0001 };
+    public:
+                                                  HierarchyInfos   ( HierarchyInfos* parent, size_t rowInParent );
+      virtual                                    ~HierarchyInfos   ();
+      virtual bool                                isRoot           () const = 0;
+      virtual bool                                isLeaf           () const = 0;
+      virtual bool                                isCollapsed      () const = 0;
+      static  int                                 getColumnCount   ();
+      static  QVariant                            getColumnName    ( int column );
+              QVariant                            getColumn        ( int column ) const;
+      virtual const HierarchyInfos*               getRow           ( int row ) const = 0;
+      inline  const HierarchyInfos*               getParent        () const;
+      inline  size_t                              getRowInParent   () const;
+      virtual int                                 size             () const = 0;
+      virtual Cell*                               getMasterCell    () const = 0;
+      virtual const Instance*                     getInstance      () const = 0;
+      virtual const std::vector<HierarchyInfos*>& getInstances     () const = 0;
+      inline  const Name                          getName          () const;
+      virtual Path                                getPath          () const;
+      virtual QString                             getFilterPattern () const = 0;
+      virtual void                                setFilterPattern ( const QString& ) = 0;
+      inline  void                                setRowInParent   ( size_t );
+      virtual void                                expand           () = 0;
+      virtual void                                collapse         () = 0;
+    protected:
+      HierarchyInfos* _parent;
+      size_t          _rowInParent;
+  };
+
+
+  inline size_t                HierarchyInfos::getRowInParent () const { return _rowInParent; }
+  inline const HierarchyInfos* HierarchyInfos::getParent      () const { return _parent; }
+  inline const Name            HierarchyInfos::getName        () const { return isRoot() ? Name("Root") : getInstance()->getName(); }
+  inline void                  HierarchyInfos::setRowInParent ( size_t rowInParent ) { _rowInParent=rowInParent; }
+
+
+// -------------------------------------------------------------------
+// Class  :  "LeafHierarchyInfos"
+
+
+  class LeafHierarchyInfos : public HierarchyInfos {
+    public:
+                                                  LeafHierarchyInfos ( const Instance*
+                                                                     , HierarchyInfos* parent
+                                                                     , size_t          rowInParent );
+      virtual                                    ~LeafHierarchyInfos ();
+      virtual bool                                isRoot             () const;
+      virtual bool                                isLeaf             () const;
+      virtual bool                                isCollapsed        () const;
+      virtual const HierarchyInfos*               getRow             ( int row ) const;
+      virtual int                                 size               () const;
+      virtual Cell*                               getMasterCell      () const;
+      virtual const Instance*                     getInstance        () const;
+      virtual const std::vector<HierarchyInfos*>& getInstances       () const;
+      virtual void                                setFilterPattern   ( const QString& );
+      virtual QString                             getFilterPattern   () const;
+      virtual void                                expand             ();
+      virtual void                                collapse           ();
+    protected:
+             const Instance*                     _instance;
+      static const std::vector<HierarchyInfos*>  _instances;
+  };
+
+
+// -------------------------------------------------------------------
+// Class  :  "InstHierarchyInfos"
+
+
+  class InstHierarchyInfos : public HierarchyInfos {
+    public:
+                                                  InstHierarchyInfos ( const Instance*
+                                                                     , HierarchyInfos* parent
+                                                                     , size_t          rowInParent );
+      virtual                                    ~InstHierarchyInfos ();
+      virtual bool                                isRoot             () const;
+      virtual bool                                isLeaf             () const;
+      virtual bool                                isCollapsed        () const;
+      virtual const HierarchyInfos*               getRow             ( int row ) const;
+      virtual int                                 size               () const;
+      virtual Cell*                               getMasterCell      () const;
+      virtual const Instance*                     getInstance        () const;
+      virtual const std::vector<HierarchyInfos*>& getInstances       () const;
+      virtual void                                setFilterPattern   ( const QString& );
+      virtual QString                             getFilterPattern   () const;
+      virtual void                                expand             ();
+      virtual void                                collapse           ();
+    protected:
+      unsigned int                  _flags;
+      const Instance*               _instance;
+      std::vector<HierarchyInfos*>  _instances;
+      QRegExp                       _filter;
+  };
+
+
+// -------------------------------------------------------------------
+// Class  :  "TopCellHierarchyInfos"
+
+
+  class TopCellHierarchyInfos : public InstHierarchyInfos {
+    public:
+                                        TopCellHierarchyInfos ( Cell*, HierarchyInfos* parent );
+      virtual                          ~TopCellHierarchyInfos ();
+      virtual bool                      isRoot                () const;
+      virtual Cell*                     getMasterCell         () const;
+      virtual const Instance*           getInstance           () const;
+              void                      setCell               ( Cell* );
+    protected:
+      Cell* _rootCell;
+  };
+
+
+// -------------------------------------------------------------------
+// Class  :  "RootHierarchyInfos"
+
+
+  class RootHierarchyInfos : public HierarchyInfos {
+    public:
+                                                  RootHierarchyInfos ( Cell* );
+      virtual                                    ~RootHierarchyInfos ();
+      virtual bool                                isRoot             () const;
+      virtual bool                                isLeaf             () const;
+      virtual bool                                isCollapsed        () const;
+      virtual const HierarchyInfos*               getRow             ( int row ) const;
+      virtual int                                 size               () const;
+      virtual Cell*                               getMasterCell      () const;
+      virtual const Instance*                     getInstance        () const;
+      virtual const std::vector<HierarchyInfos*>& getInstances       () const;
+      virtual void                                setFilterPattern   ( const QString& );
+      virtual QString                             getFilterPattern   () const;
+      virtual void                                expand             ();
+      virtual void                                collapse           ();
+              void                                setCell            ( Cell* );
+    protected:
+      std::vector<HierarchyInfos*>  _instances;
+  };
+
+
+}  // Hurricane namespace.
+
+#endif // HURRICANE_HIERARCHY_INFORMATIONS_H
diff --git a/hurricane/src/viewer/hurricane/viewer/HierarchyModel.h b/hurricane/src/viewer/hurricane/viewer/HierarchyModel.h
new file mode 100644
index 00000000..2229f5f9
--- /dev/null
+++ b/hurricane/src/viewer/hurricane/viewer/HierarchyModel.h
@@ -0,0 +1,85 @@
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Header  :       "./hurricane/viewer/HierarchyModel.h"      |
+// +-----------------------------------------------------------------+
+
+
+#ifndef  HURRICANE_HIERARCHY_MODEL_H
+#define  HURRICANE_HIERARCHY_MODEL_H
+
+#include <vector>
+#include <QFont>
+#include <QApplication>
+#include <QAbstractTableModel>
+#include "hurricane/Commons.h"
+#include "hurricane/Name.h"
+#include "hurricane/Net.h"
+#include "hurricane/Cell.h"
+#include "hurricane/viewer/Graphics.h"
+#include "hurricane/viewer/HierarchyInformations.h"
+
+
+namespace Hurricane {
+
+  class Net;
+  class Cell;
+
+
+  class HierarchyModel : public QAbstractItemModel {
+      Q_OBJECT;
+
+    public:
+                                    HierarchyModel   ( QObject* parent=NULL );
+                                   ~HierarchyModel   ();
+      inline  void                  setRootCell      ( Cell* cell );
+      virtual bool                  hasChildren      ( const QModelIndex& parent=QModelIndex() ) const;
+              QModelIndex           index            ( int row, int column, const QModelIndex& parent ) const;
+              QModelIndex           parent           ( const QModelIndex& child ) const;
+              int                   rowCount         ( const QModelIndex& parent=QModelIndex() ) const;
+              int                   columnCount      ( const QModelIndex& parent=QModelIndex() ) const;
+              QVariant              data             ( const QModelIndex& index, int role=Qt::DisplayRole ) const;
+              QVariant              headerData       ( int section, Qt::Orientation orientation, int role=Qt::DisplayRole ) const;
+      inline  Cell*                 getCell          ();
+      inline  HierarchyInfos*       getRoot          ();
+      inline  void                  setCell          ( Cell* );
+      inline  const HierarchyInfos* infosFromIndex   ( const QModelIndex& ) const;
+    private:
+      RootHierarchyInfos  _root;
+  };
+
+
+// Inline Functions.
+
+  inline Cell*           HierarchyModel::getCell   () { return  _root.getMasterCell(); }
+  inline HierarchyInfos* HierarchyModel::getRoot   () { return &_root; }
+
+
+  inline void  HierarchyModel::setCell ( Cell* cell )
+  {
+    _root.setCell( cell );
+    reset();
+  }
+
+
+  inline const HierarchyInfos* HierarchyModel::infosFromIndex ( const QModelIndex& index ) const
+  {
+    if (index.isValid())
+      return static_cast<HierarchyInfos*>(index.internalPointer());
+    return &_root;
+  }
+
+
+} // End of Hurricane namespace.
+
+
+#endif // HURRICANE_HIERARCHY_MODEL_H
diff --git a/hurricane/src/viewer/hurricane/viewer/HierarchyWidget.h b/hurricane/src/viewer/hurricane/viewer/HierarchyWidget.h
new file mode 100644
index 00000000..f643eefd
--- /dev/null
+++ b/hurricane/src/viewer/hurricane/viewer/HierarchyWidget.h
@@ -0,0 +1,111 @@
+
+// -*- C++ -*-
+//
+// This file is part of the Coriolis Software.
+// Copyright (c) UPMC 2015-2015, All Rights Reserved
+//
+// +-----------------------------------------------------------------+ 
+// |                  H U R R I C A N E                              |
+// |     V L S I   B a c k e n d   D a t a - B a s e                 |
+// |                                                                 |
+// |  Author      :                    Jean-Paul CHAPUT              |
+// |  E-mail      :            Jean-Paul.Chaput@lip6.fr              |
+// | =============================================================== |
+// |  C++ Header  :       "./hurricane/viewer/HierarchyWidget.h"     |
+// +-----------------------------------------------------------------+
+
+
+#ifndef  HURRICANE_HIERARCHY_WIDGET_H
+#define  HURRICANE_HIERARCHY_WIDGET_H
+
+#include <set>
+#include <QWidget>
+#include <QTreeView>
+#include <QItemDelegate>
+#include "hurricane/Commons.h"
+#include "hurricane/Bug.h"
+#include "hurricane/viewer/HierarchyModel.h"
+#include "hurricane/viewer/CellWidget.h"
+
+
+class QModelIndex;
+class QItemSelection;
+class QLineEdit;
+class QComboBox;
+class QHeaderView;
+
+
+namespace Hurricane {
+
+  using std::set;
+  class Net;
+  class Cell;
+
+
+// -------------------------------------------------------------------
+// Class  :  "TreeKeyFilter".
+
+
+  class  TreeKeyFilter : public QObject {
+      Q_OBJECT;
+
+    public:
+            TreeKeyFilter ( QObject* parent );
+      bool  eventFilter   ( QObject*, QEvent* );
+  };
+
+
+// -------------------------------------------------------------------
+// Class  :  "HierarchyWidget".
+
+
+  class HierarchyWidget : public QWidget {
+      Q_OBJECT;
+
+      friend class TreeKeyFilter;
+    public:
+                          HierarchyWidget   ( QWidget* parent=NULL );
+              bool        isRSelected       ( const QModelIndex& index ) const;
+      inline  CellWidget* getCellWidget     ();
+              void        rexpand           ( Path path );
+              void        rexpand           ( const QModelIndex& index );
+      inline  Cell*       getCell           ();
+      inline  void        setCellWidget     ( CellWidget* );
+              void        setCell           ( Cell* );
+              void        goTo              ( int );
+    private slots:                          
+              void        collapseHook      ( const QModelIndex& );
+              void        textFilterChanged ();
+              void        followSelected    ( const QItemSelection&, const QItemSelection& );
+    private:
+              CellWidget*     _cellWidget;
+              Cell*           _cell;
+              HierarchyModel* _baseModel;
+              QTreeView*      _view;
+              QLineEdit*      _filterPatternLineEdit;
+              int             _rowHeight;
+  };
+
+
+  inline Cell*       HierarchyWidget::getCell       () { return _cell; }
+  inline CellWidget* HierarchyWidget::getCellWidget () { return _cellWidget; }
+
+
+  inline void  HierarchyWidget::setCellWidget ( CellWidget* cw )
+  {
+    if (_cellWidget) {
+      disconnect( this, 0, _cellWidget, 0 );
+    }
+
+    _cellWidget = cw;
+    if (_cellWidget) {
+      if (_cellWidget->getTopCell()) setCell( _cellWidget->getTopCell() );
+      else                           setCell( _cellWidget->getCell() );
+    } else
+      setCell( NULL );
+  }
+
+
+} // Hurricane namespace.
+
+#endif // HURRICANE_HIERARCHY_WIDGET_H